The Plastic Beneath our Feet - Relevance and Magnitude of Microplastics in Groundwater Systems

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Abstract

The volume of globally mismanaged plastic waste has been increasing over the past decades with millions of tons being discharged into freshwater systems. While recent research has made substantial progress with regards to identifying microplastics (MP) in in surface freshwater systems such as rivers and lakes, much less is known about the magnitude and relevance of MP pollution of global groundwater resources. Despite initial field evidence of MP in groundwater aquifers, the total quantity, spatial distribution, residence time scales as well as the impact of MP on groundwater ecosystems are still completely unknown. Moreover, major sources for MP pollution of groundwater, their input pathways and fate and transport mechanisms controlling local exposures have yet to be established. Given the relevance of groundwater as our most important drinking water resource, there is a critical need to study the role of groundwater as a long-term sink for plastic pollution, including the legacy risks arising from MP reaching groundwater systems with a substantial time lag.

We present the first results of our recently started global participatory study that aims to develop a baseline of MP pollution of aquifers across the world. Such baseline data is imperative to increase our understanding of MP fate and transport processes, MP uptake by groundwater organisms and the interaction of MP with nutrients and potential co-contaminants. A specifically developed protocol allows for standardized MP sampling in boreholes, springs or wells across a wide range of geological settings and land cover classes. MP extraction and identification techniques used are specifically targeted at particles in the lower micrometre and upper nanometre range. MP particle concentrations, as well as their qualitative properties (size distributions, polymer types, additive compositions) are compared to main aquifer types and modelled transport times, landuse coverage and land (including groundwater) management practice to attribute observations to suspected sources and establish potential MP transport mechanisms and thus, also future contamination risks. With this global initiative we aim to draw attention to the potential exposure of vital groundwater resources to MP contamination and identify aquifer type dependent MP contamination risks
Original languageEnglish
Title of host publicationAGU Chicago
Publication statusPublished - 14 Dec 2022

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